LOOKING FOR MORE SPEED (help)

[dlaffert]

Hello, I have a 1994 Pulsare 2100 LD. My current set up is a 1998 Merc promax 300 with a sportmaster 1.62 gearcase. 12" of setback with a hydralic jackplate. 30" fourblade prop. I am barely hitting 80mph on gps turning at about 6000 rpm. I feel like it has more in it, but dont know where to start

Any Suggestions?!

 

[DropTop5.0]

How far below the pad is the prop at your best speed? What is max rpm for that motor?

 

[dlaffert]

the max rpm i think is 6200. I am not sure how far below the pad the propshaft is. She is away for the season. But if anything i would say the prop shaft is above the pad at max speed.

Isnt the general rule of thumb something like, for each inch of setback, the propshaft is allowed to be 1/4 inch above the pad.

So in theory, with 12" of setback you should be able to run about 3-4 inches above the pad. Thats what i was told anyway, whether or not its true i dont know.

I usually crank up the jackplate close to max height which is about 2 inches above the pad. with minimal trim and get 80mph. keeping the jackplate all the way down and using trim only gives me only about 72 mph.

I just see other 21 pulsares with 300's doing 85-90-95 on youtube. I know they have the 300X instead of the promax. but still, 80 seems a bit slow by comparison.

 

[JW]

What altitude are you boating? If you're near sea-level, then you ARE slow. But if you boat up in Denver, then you aren't doing too bad!

 

[Invader]

Using the numbers provided, you are at 24% slip which is way too much. You should be around 10-12%. There is a problem with your setup and/or prop.
http://www.go-fast.com/Prop_Slip_Calculator.htm

Maybe try another prop like a 27” Trophy. This should give you high 80s at 10% slip and 6200 rpm assuming a very light load and near sea level in altitude. Your prop shaft will need to be 0-2” above the pad with the sportmaster for best speed. I doubt a Trophy will run 3-4” above the pad due to the small 13-3/4” diameter.

Trophy props are the standard recommendation for Pulsares but I personnely have not had much luck with them. I run with a heavy load and at altitude. The Trophy’s slip way too much for me at all speeds. I like the modified Bravos and Rev 4s for the type of boating I do.